H-610-12P.. 12mm Champ Full Mortise Concealed Cylinder Hinge. In the open position the hinge has a set screw which expands the cylinder inside the hole. Just drill hole, insert and tighten the set screw! Machined solid brass with steel linkages Drill 12mm size holes to exact depth. 12mm x 1-1/16″” long for 5/8″ wood. 12mm=approximately 16/32″ diameter. Works great on things like butterfly table table leafs. Sold individually.